#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
  struct TreeNode {
      int val;
      TreeNode *left;
      TreeNode *right;
      TreeNode() : val(0), left(nullptr), right(nullptr) {}
      TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
    TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
  };
 
class Solution {
public:
    int widthOfBinaryTree(TreeNode* root) {
        vector<pair<TreeNode*, unsigned int>> as;
        unsigned int ret = 0;
        as.push_back({ root,1 });
        while (as.size())
        {
            auto& [x1, y1] = as[0];
            auto& [x2, y2] = as.back();
            ret = max(ret, y2 - y1 + 1);
            vector<pair<TreeNode*, unsigned int>> tmp;
            for (auto& [x, y] : as)
            {
                if (x->left)
                {
                    tmp.push_back({ x->left,y * 2 });
                }
                if (x->right)
                {
                    tmp.push_back({ x->right,y * 2 + 1 });
                }
            }
            as = tmp;
        }
        return ret;
    }
};